The invention relates to a device for controlling the cursor movement on a display device.
The traditional cursor controller, e.g. joystick or mouse, is not suitable for the notebook type computer system due to its size. As shown respectively in FIG. 1(A) and FIG. 1(B), a pointing stick 12 disposed on a keyboard 10 has been widely used in the notebook type computer due to its miniature structure. The state-of-art cursor controller device is disclosed in U.S. Pat. Nos. 5,521,596 and 5,640,178.
The following introduces two types of state-of-art pointing stick. The pointing stick, disclosed in U.S. Pat. No. 5,640,178 and depicted in FIG. 2(A), FIG. 2(B), includes a substrate 21 and a stick 22 connected to the substrate 21. The substrate 21 is made of resilient material. According to the different designs, the substrate 21 may be in form of three or four blades structure. Four blades structure is shown in FIG. 2(A). At the end of each blade, one female screw 211 is provided. Through the male screw 23, the pointing stick is attached to the baseplate 24 of the keyboard (not shown). The sensors 212 are respectively disposed and attached to the bottom of the substrate 21. The resistance of the sensor 212 varies responsive to the deformation of the substrate 21. During operation, by exertion of force onto the tip of the stick 22, the substrate 21 deflects and deforms. The sensor 212 deforms accordingly and a corresponding signal change is received by a controller (not shown). The controller then controls the cursor movement. As a three blades structure of the substrate is adopted, totally three sensors 212 are required.
However, for the above-mentioned pointing stick, the sensors are attached onto the substrate, and the deformation of the substrate is caused by the external force on the stick. Therefore, the substrate""s material property must have enough flexibility and the stick""s material property must have enough rigidity. These requirement place limitation on the types of material that can be used for the substrate or the stick. Furthermore, since the substrate property requires flexibility, the substrate may be easily damaged by the force exerted from the stick when the horizontal force applied on the stick exceeds a value. On the other hand, a spacing 24A, which is required to allow a vertical displacement of the substrate 21 during operation, would not allow further size reduction of the keyboard.
Another state-of-art pointing stick, shown in FIG. 3, includes a substrate 31 of rigid material and a stick 32 in rectangular column. On each of the four surfaces 321 of the column, one sensor 322 is disposed. The sensor 322 consists of two electrodes 3222, 3223, a strain gauge 3221, and a conductor 3224, which increases the conductivity. One end of the stick 32 is vertically disposed with respect to the substrate 31 and connected to the substrate 31 using a conventional approach. For instance, a female screw 311 and a corresponding male screw (not shown) may be used. The resistance of the sensor 322 varies responsive to the deflection of the stick 32. During operation, by exertion of a force onto the tip of the stick 32, the strain gauge 3221 deforms accordingly and a corresponding signal change is received by a controller (not shown). The controller then controls the cursor movement.
The rigid material of the substrate of the second type pointing stick mentioned above increases the strength of the substrate 31. The substrate 31 does not deforms during operation. Through this implementation, the substrate 31 may be attached to the keyboard baseplate without requiring a spacing, which is required for the pointing stick shown in FIG. 2(B). However, since the stick is in form of a rectangular column, four sensors are required. In addition, the sensor on each surface need one print process to make, and totally four print processes are needed to form the sensors on the. rectangular column. The corresponding print process is tedious and is not cost effective. As a result, the cost for the pointing stick of the second type can not be lowered.
A pointing stick for use to control the cursor movement on a display device is provided.
The pointing stick includes a substrate, a stick and a plurality of sensors.
One end of the pointing stick is connected to the substrate and a portion of the stick is in form of a cylinder.
The plurality of sensors are disposed over a circular surface corresponding to the cylinder of the stick.